Gas detection device

ABSTRACT

The instant disclosure provides a gas detection device including a chamber module, a light emitting module and an optical sensing module. The chamber module comprises a light condensing chamber, a receiving chamber and a sampling chamber connected between the light condensing chamber and the receiving chamber. The light emitting module is disposed on the light condensing chamber for generating a light. The optical sensing module is disposed in the receiving chamber. The sampling chamber comprises a first open end, a second open end corresponding to the first open end, a first surface, and a second surface corresponding to the first surface, the first and second open ends are connected to the light condensing chamber and the receiving chamber respectively, the first surface and the second surface are disposed between the first open end and the second open end, and the first surface is not parallel to the second surface.

BACKGROUND 1. Technical Field

The instant disclosure relates to a gas detection device, in particular,to a gas detection device for detecting the concentration of a gas.

2. Description of Related Art

The carbon dioxide detection devices or carbon dioxide analyzinginstruments in the market generally employ non-dispersive infrared(NDIR) absorption to detect the concentration of the gas. The NDIRmainly uses a calculation based on the Beer-Lambert law. The principleof such analysis is to detect the concentration of a specific gas byusing the absorption property of the gas toward infrared light having aspecific wavelength and the fact that the gas concentration isproportional to the absorption quantity. For example, carbon monoxidehas a strongest absorption to a wavelength of 4.7 micron (μm) and carbondioxide has a strongest absorption to a wavelength of 4.3 micron (μm).

However, the accuracy of the gas concentration detecting devices arelimited to the structure of the gas sampling chamber, and hence, theamount of the infrared light projected onto the infrared sensor isdecreased and the accuracy of the detection is reduced.

Regarding the conventional infrared light sensor, when the incidentlight projected onto the infrared light sensor is larger than 20degrees, the specific band width of the filter plate leads the peakvalue of the filter plate to deviate 40 nanometers (nm) toward theshorter wavelength. Therefore, a part of the light which is not lightthat can be absorbed by the gas to be measured will be projected ontothe infrared light sensor, and another part of the light related to thegas to be measured is blocked, thereby reducing the intensity of thesignal and reducing the detection accuracy. However, 20 degrees is onlyan example and the infrared light sensor can have preferably an angleother than 20 degrees in other embodiments.

Therefore, there is a need for increasing the detection accuracy of thegas concentration detection device for overcome the above disadvantage.

SUMMARY

The instant disclosure provides a gas detection device adapting innersurfaces that are not parallel to each other in the sampling chamber,thereby effectively increasing the detection accuracy of the gasconcentration.

An embodiment of the present disclosure provides a gas detection device,comprising a chamber module, a light emitting module and an opticalsensing module. The chamber module comprises a condensing chamber, areceiving chamber and a sampling chamber connected between thecondensing chamber and the receiving chamber. The light emitting moduleis disposed on the condensing chamber for generating a light. Theoptical sensing module is disposed in the receiving chamber. Thesampling chamber comprises a first open end, a second open end oppositeto the first open end, a first surface and a second surface opposite tothe first surface, the first open end is connected to the condensingchamber, the second open end is connected to the receiving chamber, thefirst surface and the second surface are disposed between the first openend and the second open end, and the first surface and the secondsurface are not parallel to each other.

Another embodiment of the instant disclosure provides a gas detectiondevice comprising a chamber module, a light emitting module and anoptical sensing module. The chamber module comprises a light condensingchamber, a receiving chamber and a sampling chamber connected betweenthe light condensing chamber and the receiving chamber. The lightemitting module is disposed on the light condensing chamber forgenerating a light. The optical sensing module is disposed in thereceiving chamber. The sampling chamber comprises a first open end, asecond open end opposite to the first open end, a first surface, asecond surface opposite to the first surface, a third surface and afourth surface opposite to the third surface. The first open end isconnected to the light condensing chamber, the second open end isconnected to the receiving chamber, the first surface, the secondsurface, the third surface and the fourth surface are disposed betweenthe first open end and the second open end and are connected to eachother sequentially, the first surface is not parallel to the secondsurface, and the third surface is not parallel to the fourth surface.

The advantage of the instant disclosure is that based on the technicalfeature of disposing the first surface and the second surface betweenthe first open end and the second open end, and the design where thefirst surface and the second surface are not parallel to each other, thegas detection device provided by the instant disclosure can effectivelyincrease the detection accuracy of the gas concentration.

In order to further understand the techniques, means and effects of theinstant disclosure, the following detailed descriptions and appendeddrawings are hereby referred to, such that, and through which, thepurposes, features and aspects of the instant disclosure can bethoroughly and concretely appreciated; however, the appended drawingsare merely provided for reference and illustration, without anyintention to be used for limiting the instant disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the instant disclosure, and are incorporated in andconstitute a part of this specification. The drawings illustrateexemplary embodiments of the instant disclosure and, together with thedescription, serve to explain the principles of the instant disclosure.

FIG. 1 is one of the three-dimensional assembly schematic views of thegas detection device of the first embodiment of the instant disclosure.

FIG. 2 is one of the three-dimensional exploded schematic views of thegas detection device of the first embodiment of the instant disclosure.

FIG. 3 is the sectional schematic view taken from line III-III in FIG.1.

FIG. 4 is one of the light projection schematic views of the gasdetection device of the first embodiment of the instant disclosure.

FIG. 5 is another light projection schematic view of the gas detectiondevice of the first embodiment of the instant disclosure.

FIG. 6 is yet another light projection schematic view of the gasdetection device of the first embodiment of the instant disclosure.

FIG. 7 is one of the three-dimensional assembly schematic views of thegas detection device of the second embodiment of the instant disclosure.

FIG. 8 is another three-dimensional assembly schematic view of the gasdetection device of the second embodiment of the instant disclosure.

FIG. 9 is one of the three-dimensional exploded schematic views of thegas detection device of the second embodiment of the instant disclosure.

FIG. 10 is another three-dimensional exploded schematic view of the gasdetection device of the second embodiment of the instant disclosure.

FIG. 11 is a three-dimensional sectional schematic view of the gasdetection device of the second embodiment of the instant disclosure.

FIG. 12 is a side schematic view of the gas detection device of thesecond embodiment of the instant disclosure.

FIG. 13 is one of the light projection schematic views of the gasdetection device of the first embodiment of the instant disclosure.

FIG. 14 is another light projection schematic view of the gas detectiondevice of the first embodiment of the instant disclosure.

FIG. 15 is an enlargement view of part A of FIG. 14.

DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Reference will now be made in detail to the exemplary embodiments of theinstant disclosure, examples of which are illustrated in theaccompanying drawings. Wherever possible, the same reference numbers areused in the drawings and the description to refer to the same or likeparts.

First Embodiment

Please refer to FIG. 1 and FIG. 2. The first embodiment of the instantdisclosure provides a gas detection device Q comprising a chambermodule, a light emitting module 2, an optical sensing module 3 and asubstrate module 4. The light emitting module 2 and the optical sensingmodule 3 can be electrically connected to the substrate module 4. Inaddition, the substrate module 4 can be electrically connected to adisplay unit (not shown), a control unit (not shown) and a processingunit (not shown). For example, the light emitting module 2 is aninfrared light emitter generating infrared light and the optical sensingmodule 3 is an infrared light sensor such as a single-channel infraredlight sensor or a double-channel infrared light sensor (in which one ofthe infrared light collecting windows is used to detect the gasconcentration and the other is used to detect the aging of the infraredlight source, and the two windows can calibrate each other). However,the instant disclosure is not limited thereto.

The gas detection device Q provided by the instant disclosure can detectthe concentration or other properties of the gas to be detected. The gasto be detected can be carbon dioxide, carbon monoxide or the combinationthereof. The instant disclosure is not limited thereto. Based on theselection of different light emitting modules 2 and optical sensingmodules 3, different gases can be measured. For example, regardingconcentration detection, different types of gases can be detected bychanging the wavelength filter (filter plate) on the optical sensingmodule 3.

Please refer to FIG. 3. The chamber module has a sampling space S, andthe chamber module comprises a condensing chamber 11, a receivingchamber 12 and a sampling chamber 13 connecting the condensing chamber11 and the receiving chamber 12. The light emitting module 2 is disposedon the condensing chamber 11 for generating light T such as infraredlight. The optical sensing module 3 comprises an optical sensing unit 31disposed in the receiving chamber 12 for receiving light T generated bythe light emitting unit 21.

As shown in FIG. 1 to FIG. 3, the chamber module 1 is constituted by theupper chamber module 1 a and the lower chamber module 1 b forfacilitating the assembly of the chamber module 1. For example, theupper chamber module 1 a and the lower chamber module 1 b can beassembled with each other by fixing members (not shown) such as screwsin the fixing holes K. The chamber module 1 can be fixed on thesubstrate module 4 by fixing the chamber module 1 through fixing members(not shown) into the fixing holes K. In the embodiments of the instantdisclosure, the substrate module 4 is a printed circuit board (PCB), thelight emitting module 2 further comprises a connecting line 22, and theoptical sensing module 3 further comprises a connecting line 32. Theconnecting line 22 of the light emitting module 2 and the connectingline 32 of the optical sensing module 3 can steadily fix the lightemitting unit 21 and the optical sensing unit 31 on the substrate module4 by soldering, thereby preventing the loose contact caused by externalforces. The sampling space S in the sampling chamber 13 can have a crosssection of a rectangular shape (in a direction perpendicular to thelength direction of the sampling chamber 13). However, the instantdisclosure is not limited thereto. In other words, in other embodiments,the cross section of the sampling space S in the sampling chamber 13 canbe a pentagon, a hexagon or a polygon.

Please refer to FIG. 2 and FIG. 3. The sampling chamber 13 comprises afirst open end 131, a second open end 132 opposite to the first open end131, a first surface 133 (such as the upper surface), a second surface134 opposite to the first surface 133 (such as the lower surface), athird surface 135 (such as the left side surface), and a fourth surface136 opposite to the third surface 135 (such as the right side surface).The first open end 131 is connected to the condensing chamber, thesecond open end 132 is connected to the receiving chamber 12, the firstsurface 133, the second surface 134, the third surface 135 and thefourth surface 136 are disposed between the first open end 131 and thesecond open end 132. The first surface 133, the second surface 134, thethird surface 135 and the fourth surface 136 are sequentially connectedto each other and form the sampling space S. In the embodiments of theinstant disclosure, the first surface 133 and the second surface 134 arenot parallel to each other. The third surface 135 and the fourth surface136 can be disposed in a way that the third surface 135 and the fourthsurface 136 are not parallel to each other as well. However, the instantdisclosure is not limited thereto.

Each of the first surface 133, the second surface 134, the third surface135 and the fourth surface 136 can have a reflective layer thereon. Thereflective layer is formed in the sampling chamber 13 by metal platingor plastic plating and is made of gold, nickel or the combinationthereof. Therefore, the sampling chamber 13 having a rectangular shapeis a rectangular optical integrator in which light T generated by thelight emitting module 2 is repeatedly reflected in the sampling chamber13, and the light intensity is integrated in the sampling chamber 13,thereby forming a uniform light distribution. In addition, the samplingchamber 13 further has one or more gas diffusing tanks 137 verticallypenetrating the first surface 133 or the second surface 134 of thesampling chamber 13. The gas diffusing tank 137 can be disposed betweenthe first open end 131 and the second open end 132 of the samplingchamber 13. In addition, the gas diffusing tank 137 can have arectangular shape.

Please refer to FIG. 4 and FIG. 5. FIG. 4 shows an implementation inwhich the first surface 133 and the second surface 134 are parallel toeach other, i.e., the implementation in the existing art. FIG. 5 showsan implementation in which the first surface 133 and the second surface134 are not parallel to each other, i.e., the implementation of theinstant disclosure. The effects of the two implementations toward thelight path are discussed below. As shown in FIG. 4, the first surface133 and the second surface 134 of the first open end 131 has a firstpredetermined distance L1 therebetween, and the first surface 133 andthe second surface 134 of the second open end 132 has a secondpredetermined distance L2 therebetween. Since the first surface 133 andthe second surface 134 are parallel to each other, the secondpredetermined distance L2 is equal to the first predetermined distanceL1.

Light T generated by the light emitting unit 21 comprises a projectionlight T1 projected onto the first surface 133 and a received light T2,the projection light T1 is reflected by the first surface 133 and thesecond surface 134 and forms the received light T2 projected onto andreceived by the optical sensing unit 31. The light emitting module 2 hasa first central axis C1 passing the light central point (not shown) ofthe light emitting unit 21. The optical sensing module 3 has a secondcentral axis C2, the second central axis C2 can pass through the centralpoint for receiving the light in the optical sensing module 3. In thefirst embodiment of the instant disclosure, the first central axis C1and the second central axis C2 are parallel to each other and arecoaxial. However, the instant disclosure is not limited thereto. Inaddition, the projection light T1 and the first central axis C1 has aprojection angle α therebetween, and the received light T2 and thesecond central axis C2 has a receiving angle β′ therebetween. Since thefirst predetermined distance L1 is equal to the second predetermineddistance L2, i.e., the first surface 133 and the second surface 134 ofthe sampling chamber 13 are parallel to each other, when the projectionangle α is 20 degrees, the receiving angle β′ is 20 degrees.

Please refer to FIG. 5. The second predetermined distance L2 of thesecond open end 132 adjacent to the optical sensing module 3 is largerthan the first predetermined distance L1 of the first open end 131adjacent to the light emitting module 2. Specifically, the light Tcomprises a projection light T1 (or referred to as the first projectionlight T11) projected onto the first surface 133 and a received light T2(or referred to as the first received light T21) received by the opticalsensing module 3. The projection light T1 and the first central axis C1have a projection angle α (or referred to as the first projection angleα₁) defined therebetween, the received light T2 and the second centralaxis C2 have a receiving angle β (or referred to as the first receivingangle β1) defined therebetween. In the embodiments of the instantdisclosure, the first central axis C1 can be parallel to a horizontalaxis HH.

Please refer to FIG. 5. In the embodiments of the instant disclosure,the slope of the first surface 133 adjacent to the first open end 131 isequal to the slope of the first surface 133 adjacent to the second openend 132, and the slope of the second surface 134 adjacent to the firstopen end 131 is equal to the slope of the second surface 134 adjacent tothe second open end 132. The projection light T1 is reflected N timesbetween the first surface 133 and the second surface 134. An inclinedangle γ is defined between the first surface 133 and the horizontal axisHH and between the second surface 134 and the horizontal axis HHrespectively. The receiving angle β between the received light T2 andthe second central axis C2 satisfies the relationship of β=α−2γN,wherein α is the projection angle, β is the receiving angle, γ is theinclined angle, and N is the number of the times of reflection. In theembodiments of the instant disclosure, the inclined angle γ is between0.1 degree to 5 degrees, preferably is between 0.3 degree to 3 degrees,more preferably is 0.5 degree. However, the instant disclosure is notlimited thereto.

In addition, the projection light T1 is reflected by the first surface133 and the second surface 134 for forming M reflected lights reflectedbetween the first surface 133 and the second surface 134 (such as thefirst reflective light R1, the second reflective light R2 and the thirdreflective light R3), and the angle between the M^(th) reflected lightand the first central axis C1 is smaller than the angle between the(M−1)^(th) reflected light and the first central axis C1. In otherwords, since both of the first surface 133 and the second surface 134have an inclined angle γ relative to the first central axis C1, theangle between a reflected light and the first central axis C1 will belarger than the angle between the previous reflected light and the firstcentral axis C1.

For example, when the projection angle α between the projection light T1and the first central axis C1 is 20 degrees, and the inclined angle γ is0.5 degree, the first angle δ1 between the projection light T1 and thefirst surface 133 can be 19.5 degrees. The projection light T1 isreflected by the first surface 133 and forms a first reflective light R1projected onto the second surface 134. Based on the law of reflection,the second angle δ2 between the first reflective light R1 and the firstcentral axis C1 is 19.5 degrees, and the third angle δ3 between thefirst reflective light R1 and the first central axis C1 is 19 degrees.The first reflective light R1 is reflected by the second surface 134 andforms a second reflective light R2 projected onto the first surface 133.The fourth angle M between the second reflective light R2 and the firstcentral axis C1 is 18 degrees. The second reflective light R2 isreflected by the first surface 133 and forms a third reflective light R3projected onto the second surface 134. The fifth angle 65 between thethird reflective light R3 and the first central axis C1 is 17 degrees.The third reflective light R3 is reflected by the second surface 134 andforms a received light T2 projected onto and received by the opticalsensing module 3. The receiving angle β between the received light T2and the first central axis C1 is 16 degrees.

In the first embodiment of the instant disclosure, the first centralaxis C1 and the second central axis C2 are coaxial and hence, thereceiving angle β between the received light T2 and the second centralaxis C2 is 16 degrees. In addition, the reflection time of theprojection light T1 by the first surface 133 and the second surface 134is 4 times (the total counts of the projection light T1 contacts thefirst surface 133 and the second surface 134). In other words, based onthe equation β=α−2γN, the receiving angle β is 20−(2*0.5*4) degrees,i.e., 16 degrees. The included angle between the second reflective lightR2 and the first central axis C1 will be smaller than the included anglebetween the first reflective light R1 and the first central axis C1.

Compared to the condition that the first predetermined distance L1 andthe second predetermined distance L2 are equal, the condition that thesecond predetermined distance L2 is larger than the first predetermineddistance L1 can receive more infrared light. In other words, thereceived light T2 preferably enters the optical sensing unit 31 in avertical direction. In addition, the projection angle α of 20 degrees isonly an example, and the instant disclosure is not limited thereto. Inother words, different optical sensing modules 3 can have differentpreferable receiving angles β. In the embodiments of the instantdisclosure, the distance between the first open end 131 and the secondopen end 132 (i.e., the length of the sampling chamber 13) can be 35millimeter (mm) to 50 mm. However, the instant disclosure is not limitedthereto.

Please refer to FIG. 6. In this embodiment, the third surface 135 andthe fourth surface 136 are inclined relative to the first central axisC1, i.e., the third surface 135 and the fourth surface 136 are notparallel to each other. Specifically, the third surface 135 and thefourth surface 136 of the first open end 131 have a third predetermineddistance L3 defined therebetween, and the third surface 135 and thefourth surface 136 of the second open end 132 have a fourthpredetermined distance L4 defined therebetween, and the fourthpredetermined distance L4 is larger than the third predetermineddistance L3.

Please refer to the description regarding FIG. 5 and FIG. 6. The light Tcomprises a first projection light T11 projected onto the first surface133 and a second projection light T12 projected onto the third surface135. The first projection light T11 is reflected by the first surface133 and the second surface 134 and forms a first received light T21projected onto and received by the optical sensing module 3. The secondprojection light T12 is reflected by the third surface 135 and thefourth surface 136 for forming a second projection light T12 projectedonto and received by the optical sensing module 3. The light emittingmodule 2 has a first central axis C1, and a first projection angle α1 isdefined between the first projection light T11 and the first centralaxis C1. A second projection angle α2 is defined between the secondprojection light T12 and the first central axis C1. The optical sensingmodule 3 has a second central axis C2, and a first receiving angle β1 isdefined between the first received light T21 and the second central axisC2. The first receiving angle β2 is defined between the second receivedlight T22 and the second central axis C2.

The first projection light T11 is reflected N₁ times between the firstsurface 133 and the second surface 134, and the second projection lightT12 is reflected for N₂ times between the third surface 135 and thefourth surface 136. The first central axis C1 and the second centralaxis C2 are both parallel to a horizontal axis HH. A first inclinedangle γ₁ is defined between the first surface 133 and the horizontalaxis HH, and between the second surface 134 and the horizontal axis HH.A second inclined angle γ₂ is defined between the third surface 135 andthe horizontal axis HH, and between the fourth surface 136 and thehorizontal axis HH. The first receiving angle β₁ between the firstreceived light T21 and the second central axis C2 satisfy the followingrelationship: β₁=α₁−2γ₁N₁. The first receiving angle β₂ between thesecond received light T22 and the second central axis C2 satisfy thefollowing relationship: β₂=α₂−2γ₂N₂. first projection angle α1 is thevalue of the first projection angle, second projection angle α₂ is thevalue of the second projection angle, first receiving angle β₁ is thefirst receiving angle, first receiving angle β₂ is the second receivingangle, first inclined angle γ₁ is the first inclined angle, secondinclined angle γ₂ is the second inclined angle, N₁ is the times ofreflection of the first projection light T11 between the first surface133 and the second surface 134, and N₂ is the number of times ofreflection of the second projection light T12 between the first surface133 and the second surface 134.

The reflection patterns of the second projection light T12 between thethird surface 135 and the fourth surface 136 are similar to that of thefirst projection light T11 between the first surface 133 and the secondsurface 134 and hence, the details are not described herein. Therefore,the implementation of the second projection angle α₂, the firstreceiving angle β₂ and the second inclined angle γ₂ are similar to thatof the first projection angle α₁, the first receiving angle β₁ and thefirst inclined angle γ₁. However, since the sampling space S of thesampling chamber 13 is a rectangular cross section, the thirdpredetermined distance L3 is larger than the first predetermineddistance L1 and the fourth predetermined distance L4 is larger than thesecond predetermined distance L2, the second inclined angle γ₂ can bebetween 0.1 degree to 5 degrees, preferably between 1 degree to 3degrees, more preferably 1.5 degrees. However, the instant disclosure isnot limited thereto.

The Second Embodiment

Please refer to FIG. 7 to FIG. 11. The second embodiment of the instantdisclosure provides a gas detection device Q′ comprising a chambermodule 1′, a light emitting module 2, an optical sensing module 3 and asubstrate module 4. Based on the comparison between FIG. 7 and FIG. 1,it is shown that the main difference between the second embodiment andthe first embodiment comprises that the chamber module 1′ provided bythe second embodiment is different from the chamber module 1 provided bythe first embodiment, and the arrangement of the optical sensing module3 of the second embodiment is different from that of the firstembodiment.

Specifically, the chamber module 1′ further comprises a light guidingportion 14 disposed between the sampling chamber 13 and the receivingchamber 12, the light guiding portion 14 has a light guiding surface141, the light guiding surface 141 reflects the projection light T1generated by the light emitting unit 21 into the optical sensing unit31. For example, the light guiding surface 141 has a reflective layermentioned before (not shown) coated thereon, or the light guidingsurface 141 is a reflective mirror. The instant disclosure is notlimited thereto. In addition, the chamber module 1′ can further comprisean open slot 15 connected between the light guiding portion 14 and thereceiving chamber 12. The second surface 134 of the sampling chamber 13and the optical sensing unit 31 have a predetermined height H (as shownin FIG. 12) defined therebetween. Therefore, the light path of the lightgenerated by the light emitting unit 21 is in a substantially “L” shapewhich starts from the light emitting unit 21 to the optical sensing unit31.

The chamber module 1′ further comprises a gas filtering membrane 16disposed on the gas diffusing tank 137. For example, the gas filteringmembrane 16 is a waterproof and air permeable membrane for avoiding thesuspended particles from entering the chamber module 1′, therebypreventing the pollution in the chamber module 1′ and ensuring thedetection accuracy. The other structures of the second embodiment aresimilar to that of the first embodiment and are not described in detailherein.

Please refer to FIG. 12. In the second embodiment of the instantdisclosure, the light guiding portion 14 is connected between the secondopen end 132 and the receiving chamber 12, and the light guiding surface141 of the light guiding portion 14 inclines for a predetermined angle θof from 30 to 60 degrees relative to the first central axis C1 or thehorizontal axis HH′ (the first central axis C1 is parallel to thehorizontal axis HH′), or the light guiding surface 141 of the lightguiding portion 14 inclines for a predetermined angle θ of from 30 to 60degrees relative to the surface of the optical sensing unit 31.Preferably, the predetermined angle θ is 45 degrees. In other words, thesurface of the optical sensing unit 31 and the horizontal axis HH areparallel to each other. In addition, preferably, the open slot 15 isconnected between the light guiding portion 14 and the receiving chamber12. In FIG. 12, the open slot 15 has a predetermined width W and thesecond surface 134 adjacent to the second open end 132 and the opticalsensing unit 31 have a predetermined height H defined therebetween, andthe predetermined width W and the predetermined height H satisfy thefollowing equation: (0.8*W)≦H≦(3*W), in which H is the predeterminedheight, and W is the predetermined width. In addition, the predeterminedheight H and the second predetermined distance L2 satisfy the followingequation: (0.8*L2)≦H≦(3*L2), in which H is the predetermined height, andL2 is the second predetermined distance. In other words, thepredetermined width W can be equal to the second predetermined distanceL2.

For example, in the embodiments of the instant disclosure, the crosssection of the rectangular sampling chamber 13 (the cross section of thesampling space S) can be larger than or equal to the sensing area of theoptical sensing unit 31. In addition, since the size of the existingdouble-channel infrared light sensor is about 4 mm*2 mm, the secondpredetermined distance L2 can be 2.1 mm, and the predetermined width Wcan be equal to the second predetermined distance L2. However, theinstant disclosure is not limited thereto. In other embodiments, thepredetermined width W can be from (1.1*L2) to (2.3*L2). Thepredetermined height H can be from 1 mm to 2 mm, preferably 1.5 mm.However, the instant disclosure is not limited thereto.

Please refer to FIG. 13 to FIG. 15. FIG. 13 shows the implementation inwhich the first surface 133 and the second surface 134 are parallel toeach other, i.e., the first predetermined distance L1 is equal to thesecond predetermined distance L2. FIG. 14 shows the implementation inwhich the first surface 133 and the second surface 134 are not parallelto each other, i.e., the first predetermined distance L1 and the secondpredetermined distance L2 are different from each other. The resultsachieved by the two implementations are described below.

The implementation of FIG. 13 is discussed under the condition that thepredetermined angle θ of the light guiding surface 141 is 45 degrees.Specifically, the light T comprises a projection light T1 projected ontothe first surface 133, the projection light T1 is reflected by the firstsurface 133 and the second surface 134 for forming an incident light T2projected onto the light guiding surface 141. The incident light T2 isreflected by the light guiding surface 141 for forming a received lightT2 projected onto and received by the optical sensing module 3. Thelight emitting module 2 has a first central axis C1, and a projectionangle α is defined between the projection light T1 and the first centralaxis C1. The optical sensing module 3 has a second central axis C2, areceiving angle β″ is defined between the received light T2 and thesecond central axis C2, and an incident angle λ′ is defined between theincident light T2 and the first central axis C1. In the secondembodiment of the instant disclosure, the first central axis C1 and thesecond central axis C2 are perpendicular to each other. However, theinstant disclosure is not limited thereto.

Please refer to the description regarding FIG. 4 set forth in the firstembodiment. Since the first surface 133 and the second surface 134 areparallel to each other, the projection angle α between the projectionlight T1 and the first central axis C1 is equal to the incident angle λbetween the incident light T2 and the first central axis C1. Theincident light T2 is reflected by the light guiding surface 141 of 45degrees and forms the received light T2 projected onto and received bythe optical sensing module 3. The receiving angle β″ between thereceived light T2 and the second central axis C2 will be equal to theprojection angle α (since the first surface 133 and the second surface134 are parallel to each other). In addition, the incident angle λ′ willbe equal to the projection angle α.

Next, please refer to FIG. 14, FIG. 15, and FIG. 5. In the followingdescription, the predetermined angle θ is 45 degrees, the inclined angleγ is 0.5 degree, and the projection angle is 20 degrees. Specifically,the light T comprises a projection light T1 projected onto the firstsurface 133. The projection light T1 is reflected by the first surface133 and the second surface 134 to form an incident light T2 projectedonto the light guiding surface 141. The incident light T2 is reflectedby the light guiding surface 141 to form a received light T2 projectedonto and received by the optical sensing module 3. As described in thefirst embodiment regarding FIG. 5, after the reflection of the firstsurface 133 and the second surface 134, the inclined angle γ between theincident light T2 and the first central axis C1 is 16 degrees. Theincident light T2 having an incident angle γ of 16 degrees is reflectedby the light guiding surface 141 and forms a received light T2 having areceiving angle β of 16 degrees.

As described in the first embodiment, the light guiding surface 141inclines for a predetermined angle θ relative to the horizontal axis HH,and the projection light T1 is reflected for N times between the firstsurface 133 and the second surface 134. The first central axis C1 isparallel to the horizontal axis HH and an inclined angle γ is definedbetween the first surface 133 and the horizontal axis HH, and the secondsurface 134 and the horizontal axis HH. The inclined angle γ between theincident light T2 and the first central axis C1 satisfies the followingrelationship: λ=α−2γN, wherein α is the projection angle, λ is theincident angle, γ is the inclined angle and N is the number of the timesof reflection.

Therefore, compared to the situation that the first predetermineddistance L1 is equal to the second predetermined distance L2, under thesituation that the second predetermined distance L2 is larger than thefirst predetermined distance L1, the optical sensing module 3 receivesmore infrared light.

[Effectiveness of the Embodiments]

In summary, the advantage of the instant disclosure is that the gasdetection device Q, Q′ provided by the embodiments of the instantdisclosure has increased accuracy based on the technical feature “thefirst surface 133 and the second surface 134 are disposed between thefirst open end 131 and the second open end 132, and the first surface133 and the second surface 134 are not parallel to each other”. In otherwords, based on the design that the second predetermined distance L2 islarger than the first predetermined distance L1, the light projectedonto the optical sensing module 3 can have a receiving angle smallerthan that of the projection angle α.

The above-mentioned descriptions represent merely the exemplaryembodiment of the present disclosure, without any intention to limit thescope of the instant disclosure thereto. Various equivalent changes,alterations or modifications based on the claims of the instantdisclosure are all consequently viewed as being embraced by the scope ofthe instant disclosure.

What is claimed is:
 1. A gas detection device, comprising: a chambermodule comprising a condensing chamber, a receiving chamber and asampling chamber connected between the condensing chamber and thereceiving chamber; a light emitting module disposed on the condensingchamber for generating a light; and an optical sensing module disposedin the receiving chamber; wherein the sampling chamber comprises a firstopen end, a second open end opposite to the first open end, a firstsurface and a second surface opposite to the first surface, the firstopen end is connected to the condensing chamber, the second open end isconnected to the receiving chamber, the first surface and the secondsurface are disposed between the first open end and the second open end,the first surface and the second surface are not parallel to each other;wherein the light comprises a projection light projected onto the firstsurface; wherein the light emitting module has a first central axis;wherein the projection light is reflected by the first surface and thesecond surface to form M reflecting lights reflected between the firstsurface and the second surface, and an included angle between the M^(th)reflecting light and the first central axis is smaller than an includedangle between the (M−1)^(th) reflecting light and the first centralaxis.
 2. The gas detection device according to claim 1, wherein thefirst surface and the second surface at the first open end have a firstpredetermined distance defined therebetween, the first surface and thesecond surface at the second open end have a second predetermineddistance defined therebetween, and the second predetermined distance islarger than the first predetermined distance.
 3. The gas detectiondevice according to claim 1, the projection light is reflected by thefirst surface and the second surface to form a received light projectedonto and received by the optical sensing module, the projection lightand the first central axis have a projection angle defined therebetween,the optical sensing module has a second central axis, the received lightand the second central axis have a receiving angle defined therebetween.4. The gas detection device according to claim 3, wherein the projectionlight is reflected between the first surface and the second surface forN times, the first central axis is parallel to a horizontal axis, aninclined angle is defined between the first surface and the horizontalaxis and between the second surface and the horizontal axis, thereceiving angle between the received light and the second central axissatisfies β=α−2γN, wherein α is the projection angle, β is the receivedangle, γ is the inclined angle, and N is the number of the times ofreflection.
 5. The gas detection device according to claim 1, wherein aslope of the first surface adjacent to the first open end is the same asa slope of the first surface adjacent to the second open end, and aslope of the second surface adjacent to the first open end is the sameas a slope of the second surface adjacent to the second open end.
 6. Thegas detection device according to claim 1, wherein the sampling chamberfurther comprises a third surface and a fourth surface corresponding tothe third surface, the third surface and the fourth surface are disposedbetween the first open end and the second open end, the first surface,the second surface, the third surface and the fourth surface areconnected to each other sequentially, and the third surface and thefourth surface are not parallel to each other.
 7. The gas detectiondevice according to claim 6, wherein the third surface and the fourthsurface at the first open end have a third predetermined distancedefined therebetween, the third surface and the fourth surface at thesecond open end have a fourth predetermined distance definedtherebetween, and the fourth predetermined distance is larger than thethird predetermined distance.
 8. The gas detection device according toclaim 1, wherein the chamber module further comprises a light guidingportion disposed between the sampling chamber and the receiving chamber,the light guiding portion has a light guiding surface, the projectionlight is reflected by the first surface and the second surface forforming an incident light projected onto the guiding surface, theincident light is reflected by the light guiding surface for forming areceived light projected onto and received by the optical sensingmodule, the projection light and the first central axis have aprojection angle defined therebetween, the incident light and the firstcentral axis have an incident angle defined therebetween, the opticalsensing module has a second central axis, the received light and thesecond central axis have a receiving angle defined therebetween.
 9. Thegas detection device according to claim 8, wherein the light guidingsurface inclines for a predetermined angle relative to a horizontalaxis, the projection light is reflected N times between the firstsurface and the second surface, the first central axis is parallel tothe horizontal axis, an inclined angle is defined between the firstsurface and the horizontal axis, and between the second surface and thehorizontal axis, the incident angle between the incident light and thefirst central axis satisfies λ=α−2γN, wherein α is the projection angle,λ, is the degree of the incident angle, γ is the degree of the inclinedangle, and N is the number of times of reflection.
 10. The gas detectiondevice according to claim 1, wherein the chamber module furthercomprises a light guiding portion disposed between the sampling chamberand the receiving chamber, the second surface adjacent to the secondopen end and the optical sensing module have a predetermined heightdefined therebetween, the predetermined height and the secondpredetermined distance satisfy (0.8*L2)≦H≦(3*L2), wherein H is thepredetermined height and L2 is the second predetermined distance. 11.The gas detection device according to claim 1, wherein the chambermodule further comprises a light guiding portion disposed between thesampling chamber and the receiving chamber, the light guiding portionhas a light guiding surface, the light guiding surface inclines for apredetermined angle of from 30 to 60 degrees relative to a horizontalaxis.
 12. The gas detection device according to claim 1, wherein thechamber module further comprises a light guiding portion disposedbetween the sampling chamber and the receiving chamber and an open slot,the open slot is connected between the light guiding portion and thereceiving chamber and has a predetermined width, the second surface ofthe sampling chamber and the optical sensing module has a predeterminedheight defined therebetween, the predetermined width and thepredetermined height satisfy (0.8*W)≦H≦(3*W), wherein H is thepredetermined height and W is the predetermined width.
 13. The gasdetection device according to claim 1, wherein the sampling chamberfurther comprises a gas diffusion tank disposed between the first openend and the second open end.
 14. The gas detection device according toclaim 1, wherein the light emitting module is an infrared light emitterand the optical sensing module is an infrared optical sensor.
 15. A gasdetection device comprising: a chamber module comprising a lightcondensing chamber, a receiving chamber and a sampling chamber connectedbetween the light condensing chamber and the receiving chamber; a lightemitting module disposed on the light condensing chamber for generatinga light; and an optical sensing module disposed in the receivingchamber; wherein the sampling chamber comprises a first open end, asecond open end opposite to the first open end, a first surface, asecond surface opposite to the first surface, a third surface and afourth surface opposite to the third surface; wherein the first open endis connected to the light condensing chamber, the second open end isconnected to the receiving chamber, the first surface, the secondsurface, the third surface and the fourth surface are disposed betweenthe first open end and the second open end and are connected to eachother sequentially, the first surface is not parallel to the secondsurface, and the third surface is not parallel to the fourth surface;wherein the light comprises a first projection light projected onto thefirst surface and a second projection light projected onto the thirdsurface, the first projection light is reflected by the first surfaceand the second surface for forming a first received light projected ontoand received by the optical sensing module, the second projection lightis reflected by the third surface and the fourth surface for forming asecond received light projection onto and received by the opticalsensing module, the light emitting module has a first central axis, thefirst projection light and the first central axis have a firstprojection angle defined therebetween, the second projection light andthe first central axis have a second projection angle definedtherebetween, the optical sensing module has a second central axis, thefirst received light and the second central axis have a first receivingangle defined therebetween, and the second received light and the secondcentral axis have a second receiving angle defined therebetween.
 16. Thegas detection device according to claim 15, wherein the first projectionlight is reflected for N₁ times between the first surface and the secondsurface, the second projection light is reflected for N₂ times betweenthe third surface and the fourth surface, the first central axis isparallel to a horizontal axis, a first inclined angle is defined betweenthe third surface and the horizontal axis and between the second surfaceand the horizontal axis, a second inclined angle is defined between thethird surface and the horizontal axis and between the fourth surface andthe horizontal axis, the first receiving angle between the firstreceived light and the second central axis satisfy β₁=α₁−2γ₁N₁, and thesecond receiving angle between the second received angle and the secondcentral axis satisfy β₂=α₂−2γ₂N₂, wherein α₁ is the first projectionangle, α₂ is the first projection angle, β₁ is the first receivingangle, β₂ is the second receiving angle, γ₁ is the first inclined angle,γ₂ is the second inclined angle, N₁ is the times of reflection of thefirst projection light between the first surface and the second surface,and N₂ is the number of times of reflection of the second projectionlight between the third surface and the fourth surface.
 17. The gasdetection device according to claim 15, wherein the slope of the firstsurface adjacent to the first open end is equal to the slope of thefirst surface adjacent to the second open end, and the slope of thesecond surface adjacent to the first open end is equal to the slope ofthe second surface adjacent to the second open end.